We feel a little guilt every time we bite into that hamburger, sub, pizza or hotdog. They may comfort the taste buds, but the fat, salt, cholesterol and sugar they contain are not welcomed by the rest of the body.

There is yet another issue that arises. It involves the packaging in which these fast foods are delivered. The hamburger is wrapped in some sort of paper, fries come in a cardboard container and that pizza may be delivered in a box. Since all these items are greasy and moist, ordinary paper won’t do. It isn’t very appetizing to pick up a hamburger wrapped in paper soaked through with grease. That’s why various chemicals are used to provide moisture and grease resistance.

This, however, is not without controversy. Ideally, the packaging material should be both hydrophobic and lipophobic, meaning that it has the ability to repel both water and fat. That is quite challenging, but there is one class of chemicals, known as polyfluoroalkyl substances (PFASs) that is up to the task. Unfortunately, PFASs are also mired in controversy.

PFAS molecules are composed of a chain of carbon atoms to which fluorine atoms are attached. It is the fluorines on the periphery of the molecule that are responsible for repelling water and fat. But the presence of the carbon-fluorine bonds, which are very strong, also makes these molecules extremely resistant to degradation. The result is that they have been detected globally in water, soil, sediment, wildlife and, alarmingly, in human blood.

Why the concern? Because some PFASs have been linked with thyroid disease, low birth weight, decreased sperm quality, higher cholesterol as well as kidney and testicular cancer. It is important, however, to understand what “linked with” means.

While there is evidence that animals treated with polyfluorinated compounds exhibit the conditions mentioned, the doses are much higher than human exposure. Furthermore, exposure of animals to a single substance is a questionable model for extrapolating to effects in people who are exposed to literally thousands of compounds, both natural and synthetic, in their food on a daily basis. There are numerous interactions possible that can mitigate the effects seen with individual compounds. As far as humans go, there have been associations with disease when blood levels of PFASs are high, as can happen with occupational exposure. However, associations can never prove that there is a cause and effect relationship. For example, people may have high blood levels of these chemicals because they eat a lot of packaged fast foods and it may be the diet that causes the problem.

Also, the specific molecular structure of the PFASs is important. It is molecules that have a chain of eight carbons that have been quite extensively studied and have been linked with health problems. Perhaps the most famous of these is perfluorooctanoic acid (PFOA), a compound that was widely used in the preparation of Teflon coatings before being phased out. It was not part of the final product, but during production some PFOA was released into the environment. DuPont and its spinoff company Chemours recently settled thousands of lawsuits, to the tune of $670 million, with residents living around plants where DuPont used PFOA. The claim was that PFOA had poisoned the water supply and caused disease.

In North America, Europe and Japan, these long chain fluorinated compounds have been phased out, but because of their resistance to biodegradation, they are still widely present in the environment. Furthermore, they are still produced elsewhere, with China and Russia being examples. In food packaging, they have been replaced by shorter chain fluorinated compounds that leave the body much more quickly and are less bio accumulative. They still do show up in the environment, but their toxicity is thought to be less than the longer chain counterparts.

A recent study that received a great deal of publicity found that 46 per cent of food contact paper, and 20 per cent of food contact cardboard contains fluorinated compounds, although to what extent isn’t clear. Nevertheless, this was enough to trigger headlines like “Not only can fast food kill you … so can the wrapper.” That is irresponsible journalism. The study did not investigate the extent to which any of these fluorinated compounds migrate into food, or whether they end up in the body of consumers. Detecting the presence of a substance does not automatically mean that it presents a risk. It is always a question of dose.

Still, there is enough smoke around these fluorinated compounds to trigger a search for alternatives. There are some, like silicones and various hydrocarbons, but they are not as functional and also have raised some toxicity concerns.

Obviously, one way to cut down on exposure to chemicals used in packaging is to rely less on packaged fast foods. And that can pay other nutritional dividends as well.

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